外源Ca对Cd胁迫下旱柳Cd吸收、亚细胞分布和化学形态的影响

Effects of exogenous Ca on Cd absorption,subcellular distribution and chemical forms in Salix matsudana L.under Cd stress

为了探究外源Ca对植物抗Cd胁迫能力的影响,以旱柳(Salix matsudana L.)为实验材料,利用水培方式进行培养,测定不同处理组(50 mmol/L Ca、50μmol/L Cd、50 mmol/L Ca+50μmol/L Cd)中旱柳培养7、14、21、28 d后的Cd、Fe、Mn的含量,同时检测了培养7 d和28 d后的旱柳根、叶不同亚细胞组分和不同化学形态的Cd含量.结果表明:①旱柳各器官均富集了不同含量的Cd,且随着Cd处理时间的延长各器官内Cd含量逐渐增加,Cd主要积累在根部,添加外源Ca可以降低各器官Cd的含量;②Cd促进了旱柳对Fe的吸收但抑制了旱柳对Mn的吸收,而外源Ca的添加促进了旱柳体内Fe的积累,缓解了Cd对植物吸收Mn元素的抑制作用;③旱柳根系中Cd含量排序为细胞壁﹥可溶性组分﹥细胞器,叶片中则为可溶性组分﹥细胞壁﹥细胞器;④添加外源Ca后,旱柳根和叶各亚细胞组分的Cd含量均显著降低(P<0.05),且可溶性组分Cd的比例有所增加,而细胞壁组分和细胞器组分中Cd的比例有所下降;⑤在旱柳中不同化学形态Cd的含量表现为CdNaCl>CdHAC>CdHCl>CdW>CdE>CdR,添加外源Ca后,各化学形态Cd含量均显著降低(P<0.05),NaCl提取态Cd所占比例增加,而醋酸和盐酸提取态Cd所占比例降低.

In order to explore the effect of exogenous Ca on the plant tolerant ability to Cd stress,Salix matsudana L.was selected as experimental material to determine the Cd,Fe and Mn content in different organs from different treatment groups(50 mmol/L Ca,50μmol/L Cd,50 mmol/L Ca+50μmol/L Cd)for 7,14,21,28 days.The materials were cultivated by hydroponic experiment method.The Cd content of different subcellular components and different chemical forms in roots and leaves of S.matsudana were also detected after 7 days and 28 days of treatment.The results were as follows:①Different organs accumulated different contents of Cd,and the Cd content in each organ increased with the extension of Cd treatment time.Cd mainly accumulated in the roots,and the addition of exogenous Ca reduced the Cd content of all the organs.②Cd promoted the absorption of Fe and inhibited the absorption of Mn in S.matsudana.The addition of exogenous Ca promoted the accumulation of Fe in S.matsudana,and alleviated the inhibitory effect of Cd on Mn accumulation.③The order of Cd content in different subcellular components of S.matsudana roots was cell wall>soluble component>organelle;The order in leaves was soluble components>cell wall>organelles.④After the addition of exogenous Ca,the Cd content in all the subcellular components of roots and leaves significantly reduced respectively(P<0.05).The percentage of Cd content in the soluble component increased,while the percentage of Cd content in the cell wall component and the organelle component decreased.⑤The Cd contents of different chemical forms in S.matsudana showed the following order:CdNaCl>CdHAC>CdHCl>CdW>CdE>CdR.Adding exogenous Ca decreased the Cd content of all the chemical forms significantly(P<0.05).The proportion of the Cd extracted in NaCl increased,while the proportion of the Cd extracted in HAC and HCl reduced.